*{
    margin: 0;padding: 0;
}
.nav{
    max-width: 900px;
    height: 30px;
    margin: 0 auto;
    border-bottom: 1px solid green;
}
.cpzs{
    max-width: 100px;
    height: 30px;
    line-height: 30px;
    border: 1px solid red;
    text-align: center;
    border-radius: 10px 0px;
    color: #fff;
    background-color: greenyellow;
}
.conter{
    margin: 0 auto;
    max-width: 900px;
    height: 500px;
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    align-items: center;
}
@media(max-width:768px){
    .conter{
        width: 33.3333%;
    }
    .nav{
        width: 33.3333%;
    }
}
@media(min-width:768px) and (max-width:1100px){
    .conter{
        width: 50%;
    }
    .nav{
        width: 50%;
    }
}
